Figure 26a. Type IIB HC of the brain in a 17-year-old girl with erosion of the adjacent calvaria. (a) Contrast-enhanced T1-weighted MR image shows a nonenhancing, low-signal-intensity multiloculated mass without edema formation in the right parietal lobe. Note also the mass effect. (b) Axial T2-weighted MR image shows increased signal intensity within the lesion. Daughter cysts are seen that are somewhat hypointense relative to the mother cyst. Note also the low-signal-intensity rim surrounding the daughter cysts. (c) Sagittal T1-weighted MR image clearly delineates the erosion of the parietal bone and the HC protrusion into the subgaleal fatty tissue. (d) Lateral radiograph of the skull shows a radiolucent lytic lesion in the parietal bone. Minimal sclerotic changes are seen at the periphery of the lesion.